The Tokamak Trap
At present, there are still “several mountains” spanning between us and real fusion reactors.
Chen Rui believes that the main difficulty of nuclear fusion lies in engineering execution. Firstly, deuterium tritium fusion typically requires a high temperature of 100 million degrees Celsius, which is seven times the temperature of the solar core, placing extremely high demands on device materials and manufacturing processes. Moreover, it is not easy to constrain high-temperature plasma under such extreme conditions.
At present, it is most necessary to solve the problems of plasma steady state and self-sustaining combustion, “said Sun Xuan. There are currently no fusion reactors worldwide that can burn for a long time, and many potential problems may not have emerged yet. For example, regarding fuel issues, if we take the deuterium tritium fusion route, since tritium does not exist in nature and needs to be artificially produced, how to produce tritium and how to achieve tritium recycling in the reaction are both problems. In addition, due to the fact that tritium is also used to manufacture nuclear weapons, national control is very strict, and commercialization may be difficult to achieve.
If measured by specific parameters, the most important aspect of nuclear fusion is to achieve a certain plasma density, temperature, and energy confinement time. Any fusion team needs to clarify the values of the three parameters based on their own technological path, “Sun Xuan pointed out. The urgent breakthrough at present is the energy constraint time, and the longer the time, the more difficult it is to break through. This is precisely the field that EAST specializes in.
Since its completion and operation in 2006, EAST on Hefei Science Island has repeatedly broken records. Its plasma has been operated over 150000 times, maintaining an international leading position in engineering physics in this field. In the mode of long pulse and high-level energy constraint, EAST has successively crossed the 60 second, 100 second, and 400 second thresholds, and achieved stable operation for 1066 seconds this year.
The high-level energy confinement mode, due to its high efficiency and strong economy, is the basic mode for stable operation of fusion experimental reactors and engineering reactors in the future. Sun Xuan believes that EAST breaking its own record means a shift in the operation mode of fusion engineering. Early Tokamaks could only intermittently output energy. The main method to achieve 24-hour uninterrupted operation is to maintain and extend the plasma current. EAST has achieved a steady state of plasma for a certain period of time through various heating methods, and these are all remarkable results.
In March 2022, the US Department of Energy held a White House summit with the theme of “Ten Year Vision for Commercialization of Fusion Energy”, listing five important fusion advances that year. Among them, EAST had already achieved discharge in high-level energy confinement mode for 400 seconds. In addition, it also includes ignition of NIF.
However, not all fusion devices can successfully complete their tasks. The most famous tokamak device internationally is undoubtedly the International Thermonuclear Experimental Reactor (ITER) located in France. The project was launched in 2006, with members including the European Union, the United States, China, and other seven parties, and has cost over 20 billion US dollars. The ITER was originally planned to be completed and put into operation in 2016. Last year, the ITER management announced that the device would not be put into operation for the first time until 2034, and the first experiment of deuterium tritium fusion would not be conducted until 2039.
ITER has also adopted a task breakdown approach, outsourcing various parts of the device to member countries or organizations for production. ITER means “road” in Latin, and its initial design was to verify the feasibility of each link in the fusion reactor, serving as a “paving the way” project. In Sun Xuan’s view, ITER may be the largest international collaborative project in human scientific research history, similar to the International Space Station. The challenges faced by such large-scale scientific engineering are also very complex, and it is impossible to predict all technical difficulties at the time of design.
Due to the long construction period, ITER may encounter various uncontrollable events. For example, as a multi country joint construction project, ITER has long had funding coordination issues and is greatly influenced by policies between countries. Sun Xuan believes that if ITER can allocate tasks based on the country’s ability level rather than contribution amount, its task process may be more reasonable. In addition, the scientific research achievements of EAST and other devices are closely related to the ultimate success of ITER. Many fusion experimental devices internationally regard the goal of ITER as a “side mission”, and the industry still hopes to see this international project ultimately succeed.
Due to the large amount of engineering and complex tasks, it may take several decades for fusion projects operated by various countries to fully achieve their goals, “Sun Xuan said.” But what can be certain is that we are already on the starting line towards fusion demonstration reactors
Commercial nuclear fusion accelerates
In the field of controllable nuclear fusion, there is an interesting “50 year law”, which states that at any historical point, the time for achieving controllable nuclear fusion is always “the next 50 years”. In the 1950s and 1960s, the successful detonation of hydrogen bombs instilled confidence in the realization of controllable nuclear fusion. But people soon realized that the theory of controlled nuclear fusion was successful, difficult to engineer, and there were few breakthroughs. Over time, the ’50 year rule’ has become deeply ingrained in people’s minds.
But commercial nuclear fusion may not necessarily be like this. After frequent delays in ITER, capital markets have also begun to target fusion startups in various countries. In Chen Rui’s eyes, 2018 is the first year of fusion development, thanks to significant advances in technology and materials, especially breakthroughs in high-temperature superconducting materials and AI technology. The implementation path of fusion energy is now clearer and more feasible.
According to the FIA report, by 2023, the global financing scale of the fusion industry will reach 6.2 billion US dollars, of which more than half will come from mid-2021 onwards. Only $270 million of the overall financing comes from government public funds, while the rest comes from the private sector.
The most radical American fusion company is Helion Corporation. The company was founded in 2013, with investors including OpenAICEO Sam Ultraman. At the end of 2024, Ultraman revealed to the media that Helion will soon demonstrate net energy gain nuclear fusion. Microsoft has signed a bet agreement with Helion to purchase nuclear fusion power provided by Helion in 2028, with a power of no less than 50 megawatts. This number is small but significant, exceeding the annual power generation capacity of 42 megawatts of top wind farms in the United States. Many industry insiders say that if Helion can deliver, it will be a ‘historic moment’.
Helion rarely discloses its technical roadmap and parameters. Sun Xuan entered Los Alamos National Laboratory in the United States in 2006 to learn about the development of fusion technology in the country. He pointed out that Helion’s technology is based on the deep history of field inversion configuration (FRC) research in the United States. FRC is a fusion pathway different from Tokamaks, with a linear fusion device. In general linear devices, particles are easily dispersed along a straight line, but if a closed magnetic field structure is formed inside the device through magnetic field reversal, particle confinement can also be achieved.
The particle heat flux, wall materials, superconductivity, and other issues of circular tokamak can theoretically be avoided by FRC, therefore, this route has received much attention in recent years. Sun Xuan stated that based on publicly available information, Helion has noticed the plasma confinement and instability issues caused by FRC, and fusion energy conversion based on FRC has a high possibility of success. Chen Rui holds a cautiously optimistic attitude towards Helion’s radical plan, believing that it remains to be seen in the absence of more public information.
Whether successful or not, the expansion of technological routes is a significant contribution to the commercialization of fusion. When Tokamaks encounter many engineering difficulties and companies need compact fusion devices to quickly achieve results transformation, they will naturally explore more theories to obtain similar results. For example, Helion targets deuterium and helium-3 fusion. There is a large reserve of helium-3 on the moon, which can solve the fuel source problem. FRC may be the most suitable technology route for non deuterium and tritium fusion, therefore it has been adopted by Helion.
Industry insiders believe that the cost of electricity required for nuclear fusion reactions, as well as the cost of device research and development, manufacturing, and maintenance, are not low. How to achieve economic benefits while promoting technological breakthroughs is also a difficult point for the true application of “artificial sun”. Sun Xuan pointed out that many foreign companies have begun to use technology to produce by-products, such as producing radioactive medical isotopes. It is still worth exploring how domestic enterprises can “lay eggs along the way” to achieve the transformation of achievements. Plasma related technologies can also be used for nuclear waste treatment in current nuclear fission substations.
Fusion is a major strategic requirement for the country, and the scale of investment will only increase until it is realized, “said Sun Xuan. In November 2023, the State owned Assets Supervision and Administration Commission of the State Council explicitly stated that controllable nuclear fusion is an important direction for future energy development, and encouraged more enterprises to join the development of controllable nuclear fusion. After commercialization and marketization, there will definitely be a head effect. However, the fusion market is very large and can accommodate enough companies to compete together
From the timeline of star ring energy gathering, it can be seen that it has taken the first step towards commercialization. In July 2023, it collaborated with Tsinghua University to construct the preliminary validation device SUNIST-2. Next, Star Ring Energy will develop the next-generation technology validation device CTRFR-1, aimed at thoroughly verifying the engineering feasibility of controllable fusion, and is expected to be achieved around 2028. Afterwards, Xinghuan Energy will begin construction of the commercial fusion demonstration reactor CTRFR-2, which will begin at the end of 2028 and be completed within 3-5 years.
Sun Xuan is more optimistic. He is also the founder of fusion enterprise Xingneng Xuanguang, and he expects Xingneng Xuanguang to achieve fusion power production within 5 years. Enterprises rarely choose the exact same technological route as the ‘national team’, and there is also a high degree of technological differentiation between enterprises, which is conducive to risk management and approaching commercialization from different perspectives
